1. Field of the Invention
The present invention relates to a tactile-feedback rotary electrical component that is suitably used in electronic devices such as microwave ovens and acoustic devices.
2. Description of the Related Art
As an example of a conventional tactile-feedback rotary electrical component, a rotary variable resistor will be described below with reference to FIGS. 12 and 13. Referring to FIG. 12, an operating member 52 is rotatably mounted in a cup-shaped metal cover 51.
In the operating member 52, an operating section 53 and a disklike rotating section 54 are integrally formed. The rotating section 54 is held inside the cover 51, and the operating section 53 protrudes from the cover 51.
An insulating substrate 57 with resistors 55 and the conductors 56 is attached to the open end of the cover 51, and a sliding element 58 mounted on the rotating section 54 is in sliding contact with the resistors 55 and the conductors 56.
A metal leaf spring 59 includes a zigzag portion 59a bent in a zigzag form, and a semicircular protuberance 59b at the end thereof.
The leaf spring 59 is mounted in a hole 54a formed in the rotating section 54 so that the protuberance 59b engages with and disengages from a recess 51a formed in the cover 51.
When the operating section 53 is rotated, the rotating section 54 is also rotated. The sliding element 58 slides on the resistors 55 and the conductors 56 to change the resistance, and the protuberance 59b of the leaf spring 59 engages with and disengages from the recess 51a of the cover 51 to give tactile feedback in the rotation of the operating section 53.
In the above-described conventional tactile-feedback rotary electrical component, since the leaf spring 59 for obtaining tactile feedback is mounted in the rotating section 54, it must be mounted in the cover 51 while being held in the rotating section 54. This reduces assembly efficiency and increases cost.
Since the hole 54a of the rotating section 54 holds the zigzag leaf spring 59 therein, it must be large enough to allow the leaf spring 59 to move in the direction perpendicular to the axial direction. For this reason, the leaf spring 59 is fitted loosely and rattles in the axial direction of the operating section 53, thereby degrading the tactile feedback.
Since the leaf spring 59 has a zigzag shape, workability is decreased and the cost is increased.
Since the zigzag leaf spring 59 is mounted in the hole 54b of the rotating section 54, when the rotating section 54 is decreased in thickness and size for the purpose of reducing the size of the rotary electrical component, the leaf spring 59 is also decreased in size. In particular, this makes it difficult to obtain a high torque.
Accordingly, it is an object of the present invention to provide an inexpensive tactile-feedback rotary electrical component with high assembly efficiency.
In order to overcome the above problems, according to an aspect of the present invention, there is provided a tactile-feedback rotary electrical component including: a housing; an operating section rotatably mounted in the housing; a rotating section held in the housing to be rotated by the operating section; and a first U-shaped spring formed of a leaf spring, wherein the first U-shaped spring is held in a recessed holder section formed in the housing, one of the outer peripheral surface of the rotating section and the first U-shaped spring has a protuberance, the other has a recess, and the protuberance and the recess are engaged and disengaged by the rotation of the rotating section so as to produce tactile feedback.
Preferably, the rotating section has the recess, and the first U-shaped spring has the protuberance.
Preferably, the protuberance is shaped like a rib, and the recess is shaped like a groove.
Preferably, the housing has a cylindrical wall section having an open end portion opened at the rear end, the holder section is formed in the wall section, and the first U-shaped spring is held in the holder section so as to be placed along the axial direction of the operating section.
Preferably, two first U-shaped springs are mounted in the holder section, and the sliding paths of the protuberances of the two first U-shaped springs with respect to the rotating section are different from each other.
Preferably, the recessed holder section includes an open portion facing the open portion of the wall section at one end in the axial direction of the operating section, and an inner portion. Preferably, one of the first U-shaped springs is placed so that a free end portion thereof is disposed on the side of the open portion of the holder section and so that a connecting portion thereof is disposed in the inner portion, and the other U-shaped spring is placed so that a connecting portion thereof is disposed on the side of the open portion of the housing and so that a free end portion thereof is disposed in the inner portion. Preferably, the sliding paths of the protuberances of the two first U-shaped springs with respect to the rotating section are different from each other.
The tactile-feedback rotary electrical component may further include a second U-shaped spring formed of a leaf spring for elastically pressing the outer peripheral surface of the rotating section.
Preferably, the wall section of the housing has a polygonal outer wall, and the holder section is formed on the inner wall of the wall section facing the corner of the outer wall.
Preferably, at least the first U-shaped spring is held in one of the plural holder sections, the first or second U-shaped spring is held in the other holder section, and the rotating section is elastically pressed toward the rotation center by the plural U-shaped springs.